"You hear loud quaking from deep underground..."
The Mecha Biome is an Extreme Mode biome created when the Wall of Steel MK-II is defeated.
Iron Slime (My Version)
Mad Zombie Scientist
Guardian Prime (Mini-Boss)
Mechanical Slime King
Skeletron Prime MK-II
The Mechanical Omnipresence
The Destroyer of Worlds
The Core of Mechanisms
The Titanium Killer
-The "CoreTera" is a portmanteau of "Core" and "Plantera".
-Ocram in reverse is "Marco", which is a reference to the developer who made Ocram.
-Guardian Prime cannot be found after beating Skeletron Prime MK-II, since the boss protects the Mech Dungeon.
Mechanical Dungeon (My Version)
Mechanical Jungle (My Version)
Underground Mechanical Jungle
Mecha Biome Overworld (Mechanical Purity) Theme